Vitamin D Status of Preterm Newborns at Approximately 4 Weeks of Age in Shenzhen, China: A Retrospective Observational Cohort Study Conducted Across Two Centers

Abstract

Background and Objectives

To examine the correlation between the concentration of vitamin D (VD) in venous blood at approximately 4 weeks of age (±4 weeks of age) and neonatal outcomes in preterm infants (birth weight <1500 g or gestational age <32 weeks) in two neonatal intensive care units (NICUs) located in Shenzhen, China.

Methods and Study Design

Preterm infants were split into two groups based on their VD concentration at ±4 weeks of age: VD insufficiency (VDI) group (≤20 ng/mL) and VD sufficient (VDS) group (>20 ng/mL). Binary logistic regression analysis was used to examine relationships between outcomes and VDI.

Results

Of 230 infants in total, 119 (51.7%) were assigned to the VDI group and 111 to the VDS group (48.3%). No correlation was found between serum VD at ±4 weeks of age and gestational age (p>0.05). The starting point of the two groups for oral VD intake did not differ significantly (p>0.05). At ±4 weeks of age, oral VD dose (P<0.05) was greater in the VDS group. Gestational diabetes mellitus was associated with VDI (OR=1.94, 95% CI 1.01–3.75, p=0.047) after controlling for this risk. Following correction for gestational age and oral VD dosage at ±4 weeks old, VDI was also linked to a significant risk of retinopathy of prematurity (OR=2.00, 95% CI 1.08–3.68, p<0.027).

Conclusion

Preterm newborns (gestational age <32 weeks or birth age <1500 g) in NICUs in Shenzhen, China continue to have significantly high VDI. Higher VDI is associated with gestational diabetes mellitus and retinopathy of prematurity.

Keywords:

• very preterm birth
• very low birth weight infant
• vitamin D
• 4 weeks of age
• outcome

Data Sharing Statement

The corresponding author may obtain any data from the study upon reasonable request, [email protected] (Yanping Guo).

Acknowledgments

We are grateful to all the children and their families for participating in this research.

Disclosure

The authors have no conflicts of interest to declare in this work.

Additional information

Funding

This work was supported by the General Program for Clinical Research at Peking University Shenzhen Hospital [grant number LCYJ2020013]. Clinical trial registration number: ChiCTR2100048293.